There exist a number of known methodologies and apparatuses for treating the surface of a work piece. For purposes of this document, the term "treatment" or "treating" will be understood to encompass abrading, cutting, polishing, and/or otherwise modifying the surface of a work piece. The term "work piece" will be understood to include any and all materials which can be operated upon by such methods and apparatuses for the purpose of abrading or otherwise treating them.
One type of treatment is referred to as "sandblasting" which is a generic term which is understood to designate any of a series of processes in which small particles are propelled against the surface to effect changes at or on that surface. For example, sandblasting is commonly used to remove unwanted material from the surfaces of objects by abrasion or erosion. However, sandblasting techniques have also been developed which can alter the physical condition of the surface of an object, such as by shot peening. Another technique for abrading or otherwise treating materials is to use a high velocity water jet to achieve the desired surface treatment. Water jets can also be used to cut certain materials, much like a saw.
One drawback with both sandblasting and water jet technologies relates to clean-up or removal of abrasive particles after they have been used. Similarly, water jet technology suffers from problems relating to the collection of the water released during the cutting or abrading operation, as well as problems of possible contamination of the water from the eroded material.
One attempt to solve the above problems relates to the use of sublimable particles, such as dry ice, as an abrasive material. The primary advantage of using sublimable particles (i.e., particles that change directly from a solid to a gas without the transition through the liquid state) in a sandblasting operation is that there is no secondary waste material to be collected. That is, the dry ice particles change to gaseous carbon dioxide (CO.sub.2) shortly after striking the surface of the object. The gaseous carbon dioxide can then be discharged into the atmosphere. Since carbon dioxide is present in the atmosphere in substantial quantities, venting the carbon dioxide gas into the atmosphere generally does not pose any problems.
This invention arose out of concerns associated with providing improved methods and apparatuses for surface treatment of a work piece. In particular, this invention arose out of concerns associated with providing improved methods and apparatuses which use sublimable particles to effectuate a desired surface treatment.